Alzheimer’s disease (AD) is an invariably fatal neurodegenerative disorder and the leading cause of senile dementia worldwide. There is no effective treatment and limited functionality for early unequivocal diagnosis. Now, a study led by researchers at Cedars-Sinai provides the scientific basis for using noninvasive eye imaging to detect the pathological hallmarks of Alzheimer’s. The team state their experimental technology scans the retina using techniques which can identify beta-amyloid protein deposits that mirror those in the brain. The opensource study is published in the journal JCI Insight.

Previous studies show that accumulations of neurotoxic beta-amyloid protein in the brain of AD patients can be detected with positron emission tomography (PET) and analysis of cerebrospinal fluid, however, these are invasive, inconvenient and costly. Past studies from the lab provided the first evidence for the existence of Alzheimer’s-specific plaques in the human retina, and demonstrated the ability to detect individual plaques in live mouse models using a modified ophthalmic device. The current study supports translation of the group’s retinal optical imaging approach to humans, which demonstrates the feasibility to detect and quantify retinal amyloid deposits in living patients in a proof-of-concept human trial.

The current study demonstrates the feasibility to noninvasively detect and quantify amyloid deposits in the retinas of live human subjects by using a solid lipid curcumin fluorochrome and a modified point Scanning Laser Ophthalmoscope (SLO). In a subset of human samples, the lab assessed the correlation between retinal and cerebral plaques and coexistence of retinal neuronal loss. Results show that this is the first histologic quantitative analysis of retinal plaque clusters, or ‘hot spots,’ containing the most toxic forms of beta-amyloid with specific distribution patterns in superior peripheral regions that were previously unexplored.

The team state that they present a quantitative and detailed histological report of retinal beta-amyloid deposits and the pathological hallmarks of AD, including their distribution and ultrastructure in AD patients, together with the demonstrated feasibility to noninvasively image and quantify retinal amyloid deposits in living patients. They go on to add that such retinal amyloid imaging technology, capable of detecting discrete deposits at high resolution, may present a sensitive yet inexpensive tool for screening populations at risk of AD, assessing disease progression, and monitoring response to therapy.

The team surmise that their data is the first report of certain Alzheimer’s-related pathologies in the retina, including vascular amyloid pathology; and the demonstration of a significant correlation between retinal and brain plaques, and coexistence of neuronal loss. For the future, the researchers state that the next step is to continue with clinical trials to ensure the technology is ready for the medical community to help manage this disease.